Abstract We present a novel user-space and transaction-oriented protocol for use in high-performance distributed computing applications. The TRAP protocol is designed to support low-latency communication in multithreaded message-passing libraries. To demonstrate the viability of TRAP, we implemented and tested the fully operational protocol and conducted several experiments comparing its runtime performance with that of popular communication libraries. For fairness, the experiments did not exploit the TRAP protocol's multithreading capability at the application level. The results show that a TRAP-based communication library can, in various scenarios, outperform extant libraries based on in-kernel or user-level protocols. The results of these experiments also show that the TRAP protocol exhibits scalability characteristics, with respect to number of computing and communicating nodes, that is superior to regular in-kernel TCP/IP and other user-space protocol implementations.